Grout Lift Height and Missing Prism Samples
On a 20-ft-tall reinforced concrete masonry wall, the approved TMS 602 specification limits grout lifts to 8 ft and requires one set of grout or prism samples per 5,000 sq ft of wall area. The wall is 18,000 sq ft. The inspector documents that the contractor placed three lifts of 10 ft each in one day on the east wall using a 10-in. grout pump. No grout samples have been taken, although 6,000 sq ft is complete. The contractor argues that the mix had a 9-in. slump and was "pumped wet," so consolidation is fine. After formwork is stripped on a pilaster, the inspector finds a 2-in.-deep void at a construction joint. The contractor wants to fill the void with mortar and continue.
1. Evaluate the lift-height and sampling deficiencies. What should the inspector do?
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The 10-ft lifts exceed the approved 8-ft limit and the TMS 602 default for coarse grout, so the work is nonconforming regardless of slump. A 9-in. slump may be within the grout mix range, but it does not justify exceeding lift height; high lift heights increase the risk of voids, segregation, and incomplete consolidation, especially around reinforcement. The missing samples are also a quality-assurance failure: the approved rate requires sampling at 5,000-sq-ft intervals, and 6,000 sq ft is complete with zero samples. The inspector should issue a nonconformance report, notify the contractor and EOR in writing, stop further grouting until the EOR and inspection plan are followed, and require an evaluation of the already placed wall. The inspector cannot waive sampling or accept the lift-height deviation based on the contractor's opinion.
2. How should the 2-in. void be handled, and what testing or repair options are appropriate?
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The void is visible evidence of incomplete consolidation at a construction joint and must be evaluated before any cosmetic repair. Filling with ordinary mortar is not acceptable without EOR approval because mortar is not a structural repair material for a void in grouted masonry. The inspector should document the location, size, and depth, and require the EOR to evaluate the effect on capacity and durability. Options may include removal and replacement of the affected pilaster section, a non-shrink structural repair grout approved by the EOR, or additional testing such as cores or nondestructive evaluation to determine the extent. If the EOR accepts a repair, the inspector should require a repair procedure, surface preparation, and verification. The contractor should not continue production until the root cause of the void and the lift-height problem is corrected.